fallout

The precipitation to the earth of radioactive particles from the smoke and vapor

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produced by burst of an atomic weapon when

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the violence of the disturbance has subsided,

After the detonation of a weapon, metallic

oxide particles in the atomic cloud collide
with particles of dirt (or with droplets of

water as well as materia] from the bottom.)

up in the rising column.. These particles
or droplets become contaminated with radioactivity amd they gradually fall back to

earth, sometimes after having been carried
considerable distances downwind,

film badge

Radioactivity sensitive device worn to
indicate amount of radiation received.

fireball

The luminous sphere of hot gases which form
a few millionths of a second after detonation of an atomic weapon and immediately

starts expanding and cooling, -In a nominal
atomic bomb explosion, the ball of fire

reaches a maximum radius of about 450 feet,

firing system

1. For an implosion weapon, that portion
of the weapon which, upon signal from the
arming system, transforms and stores electrical
energy, and, upon signal from the fuzing

system, discharges this stored electrical
energy to detonate the implosion system,

This firing system will normally consist of

the firing set, firing switch, load coils,
load plates, detonator cables, other

connecting cables, and structure,

2. For gun-assembly weapons, that portion
of the weapon which receives a signal to

ignite a pyrotechnic powder train, which in

turn ignites the propellant,
fission

Although fission of heavy nuclei can be

brought about in a number of ways, there is
only one that is of importance for the

practical release of nuclear energy:

This

is the fission initiated by neutrons. The
reason is that the fission process is itself
accompanied by the liberation of neutrons, so
that a chain reaction with the continuous
release of energy is possible, Three of the
isotopes which can be used in a fission chain

process are Uranium-233, Uranium-235, and
322

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